Implements the command line interface `butler convert` subcommand,
should only be called by command line tools and unit test code that tests
this function.
Convert the gen 2 Butler repo at `gen2root` into a gen 3 repo
living at `repo`.
Parameters
----------
repo : `str`
URI to the gen 3 repository.
gen2root : `str`
URI to the gen 2 repository.
skymap_name : `str` or None
Name of the skymap to be converted in the repo.
skymap_config : `str` or None
Path to the `lsst.skymap.BaseSkyMapConfig` of the gen2 skymap to be
converted.
calibs : `str` or None
Path to the gen2 calibration repository to be converted.
If a relative path, it is assumed to be relative to `gen2root`.
reruns : `list` [`str`] or None
List of rerun paths to convert. Output collection names will be
guessed, which can fail if the Gen2 repository paths do not follow a
recognized convention. In this case, the command-line interface cannot
be used.
config_file : `str` or None
Path to `lsst.obs.base.ConvertRepoConfig` configuration to load
after all default/instrument configurations.
transfer : `str` or None
Mode to use when transferring data into the gen3 repository.
processess : `int`
Number of processes to use for conversion.
Definition at line 35 of file convert.py.